drm/mcde: Use mode->clock instead of reverse calculating it from the vrefresh

htotal*vtotal*vrefresh ~= clock. So just say "clock" when we mean it.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428171940.19552-12-ville.syrjala@linux.intel.com

drivers/gpu/drm/mcde/mcde_dsi.c

@@ -537,8 +537,7 @@ static void mcde_dsi_setup_video_mode(struct mcde_dsi *d,
 	 * porches and sync.
 	 */
 	/* (ps/s) / (pixels/s) = ps/pixels */
-	pclk = DIV_ROUND_UP_ULL(1000000000000,
-				(drm_mode_vrefresh(mode) * mode->htotal * mode->vtotal));
+	pclk = DIV_ROUND_UP_ULL(1000000000000, mode->clock);
 	dev_dbg(d->dev, "picoseconds between two pixels: %llu\n",
 		pclk);